The present invention relates to motors and specifically to a dust-proof sealing structure for a motor which rotates and drives magnetic discs in a magnetic disc apparatus of a computer.
Conventionally, a motor for rotating and driving magnetic discs comprises a cylindrical frame within which is a shaft with both ends supported by at least a pair of bearings. Magnetic discs are secured to the frame and rotated generally at 3,600 r.p.m.; such apparatus generally utilizes dust-proof seals, such as magnetic fluid seals or labyrinth seals.
The use of a magnetic fluid seal to prevent the entry of dust onto the magnetic heads results in an unacceptably high manufacturing cost, as magnetic fluids are expensive. Further, the surfaces of adjacent parts must be machined to a high tolerance to assure an absence of leaks. In addition, a longer shaft is required to provide a seal with magnetic fluid.
Should labyrinth seals be used to protect the magnetic discs from the effects of dust, it is necessary to uniformly and minutely form mating channels with seats of complicated cross-section, necessitating difficult machining and increased expenditures in machining and assembly work.